/******************************************************************************** Implementation of cached Qt SQL result classes****** Copyright (C) 1992-2003 Trolltech AS.  All rights reserved.**** This file is part of the sql module of the Qt GUI Toolkit.**** This file may be distributed under the terms of the Q Public License** as defined by Trolltech AS of Norway and appearing in the file** LICENSE.QPL included in the packaging of this file.**** This file may be distributed and/or modified under the terms of the** GNU General Public License version 2 as published by the Free Software** Foundation and appearing in the file LICENSE.GPL included in the** packaging of this file.**** Licensees holding valid Qt Enterprise Edition licenses may use this** file in accordance with the Qt Commercial License Agreement provided** with the Software.**** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.**** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for**   information about Qt Commercial License Agreements.** See http://www.trolltech.com/qpl/ for QPL licensing information.** See http://www.trolltech.com/gpl/ for GPL licensing information.**** Contact info@trolltech.com if any conditions of this licensing are** not clear to you.************************************************************************/#include "qsqlcachedresult.h"#include <qdatetime.h>#ifndef QT_NO_SQLstatic const uint initial_cache_size = 128;class QtSqlCachedResultPrivate{public:    QtSqlCachedResultPrivate();    bool seek(int i);    void init(int count, bool fo);    void cleanup();    QtSqlCachedResult::RowCache* next();    void revertLast();    QtSqlCachedResult::RowsetCache *cache;    QtSqlCachedResult::RowCache *current;    int rowCacheEnd;    int colCount;    bool forwardOnly;};QtSqlCachedResultPrivate::QtSqlCachedResultPrivate():    cache(0), current(0), rowCacheEnd(0), colCount(0), forwardOnly(FALSE){}void QtSqlCachedResultPrivate::cleanup(){    if (cache) {	for (int i = 0; i < rowCacheEnd; ++i)	    delete (*cache)[i];	delete cache;	cache = 0;    }    if (forwardOnly)	delete current;    current = 0;    forwardOnly = FALSE;    colCount = 0;    rowCacheEnd = 0;}void QtSqlCachedResultPrivate::init(int count, bool fo){    cleanup();    forwardOnly = fo;    colCount = count;    if (fo)	current = new QtSqlCachedResult::RowCache(count);    else	cache = new QtSqlCachedResult::RowsetCache(initial_cache_size);}QtSqlCachedResult::RowCache *QtSqlCachedResultPrivate::next(){    if (forwardOnly)	return current;    Q_ASSERT(cache);    current = new QtSqlCachedResult::RowCache(colCount);    if (rowCacheEnd == (int)cache->size())	cache->resize(cache->size() * 2);    cache->insert(rowCacheEnd++, current);    return current;}bool QtSqlCachedResultPrivate::seek(int i){    if (forwardOnly || i < 0)	return FALSE;    if (i >= rowCacheEnd)	return FALSE;    current = (*cache)[i];    return TRUE;}void QtSqlCachedResultPrivate::revertLast(){    if (forwardOnly)	return;    --rowCacheEnd;    delete current;    current = 0;}//////////////QtSqlCachedResult::QtSqlCachedResult(const QSqlDriver * db ): QSqlResult ( db ){    d = new QtSqlCachedResultPrivate();}QtSqlCachedResult::~QtSqlCachedResult(){    delete d;}void QtSqlCachedResult::init(int colCount){    d->init(colCount, isForwardOnly());}bool QtSqlCachedResult::fetch(int i){    if ((!isActive()) || (i < 0))	return FALSE;    if (at() == i)	return TRUE;    if (d->forwardOnly) {	// speed hack - do not copy values if not needed	if (at() > i || at() == QSql::AfterLast)	    return FALSE;	while(at() < i - 1) {	    if (!gotoNext(0))		return FALSE;	    setAt(at() + 1);	}	if (!gotoNext(d->current))	    return FALSE;	setAt(at() + 1);	return TRUE;    }    if (d->seek(i)) {	setAt(i);	return TRUE;    }    setAt(d->rowCacheEnd - 1);    while (at() < i) {	if (!cacheNext())	    return FALSE;    }    return TRUE;}bool QtSqlCachedResult::fetchNext(){    if (d->seek(at() + 1)) {	setAt(at() + 1);	return TRUE;    }    return cacheNext();}bool QtSqlCachedResult::fetchPrev(){    return fetch(at() - 1);}bool QtSqlCachedResult::fetchFirst(){    if (d->forwardOnly && at() != QSql::BeforeFirst) {	return FALSE;    }    if (d->seek(0)) {	setAt(0);	return TRUE;    }    return cacheNext();}bool QtSqlCachedResult::fetchLast(){    if (at() == QSql::AfterLast) {	if (d->forwardOnly)	    return FALSE;	else	    return fetch(d->rowCacheEnd - 1);    }    int i = at();    while (fetchNext())	i++; /* brute force */    if (d->forwardOnly && at() == QSql::AfterLast) {	setAt(i);	return TRUE;    } else {	return fetch(d->rowCacheEnd - 1);    }}QVariant QtSqlCachedResult::data(int i){    if (!d->current || i >= (int)d->current->size() || i < 0)	return QVariant();    return (*d->current)[i];}bool QtSqlCachedResult::isNull(int i){    if (!d->current || i >= (int)d->current->size() || i < 0)	return TRUE;    return (*d->current)[i].isNull();}void QtSqlCachedResult::cleanup(){    setAt(QSql::BeforeFirst);    setActive(FALSE);    d->cleanup();}bool QtSqlCachedResult::cacheNext(){    if (!gotoNext(d->next())) {	d->revertLast();	return FALSE;    }    setAt(at() + 1);    return TRUE;}int QtSqlCachedResult::colCount() const{    return d->colCount;}#endif // QT_NO_SQL